+ All Categories
Home > Documents > Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons +...

Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons +...

Date post: 16-Jan-2016
Category:
Upload: beverly-harper
View: 237 times
Download: 0 times
Share this document with a friend
14
Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons
Transcript
Page 1: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Number of Protons = Number of ElectronsNumber of Protons = Atomic NumberAtomic Mass = Protons + Neutrons

Page 2: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Average Atomic Mass

Page 3: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Average Atomic Mass

The atomic masses reported in the periodic table represent the weighted average of the masses of the naturally occurring isotopes of that element

Page 4: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Weighted Avg. of Test Grades

Suppose you have: 1 test of 0% and 9 tests of 90% What if I said your average was 45?

(0 + 90 = 90; Divide by 2 = 45)

Would you be happy?

Page 5: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

NO!

The long way to do this problem:

(90 + 90 + 90 + 90 + 90 + 90 + 90 + 90 + 90 + 0) 10

Average = 81% I bet you like this a lot better!

Page 6: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

The smart way to do this problem!

grades of 90: 9 out of 10 is 90% grade 0f 0: 1 out of 10 is 10%

So 90% of the test grades are 90 10% of the test grades are 0

(0.90 X 90) + (0.10 X 0) = 81 + 0

Average = 81%

Page 7: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Weighted average:Weighted average:

Smarter way to calculate Smarter way to calculate the average if you have the average if you have

numerous items to numerous items to averageaverage

Page 8: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Method of Weighted Averages

● Convert % to decimal format (Divide % by 100)

● Multiply each isotope’s abundance factor by its atomic mass

● Find the Sum

Page 9: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Avg. Atomic Mass of Chlorine

36.966 amu24.230%Isotope 2Isotope 2

34.969 amu75.770%Isotope 1Isotope 1

MassMassPercent Percent AbundanceAbundance

Chlorine has two isotopes.

Page 10: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Avg. Atomic Mass of Chlorine =

(.75770)(34.969 amu) + (.75770)(34.969 amu) +

(.24230) (36.966 amu) (.24230) (36.966 amu)

= 26.496 amu + 8.957 amu= 26.496 amu + 8.957 amu

= 35.453 amu= 35.453 amu

Convert % to Convert % to decimalsdecimals

Multiply by Multiply by appropriate appropriate massmass

SumSum

Page 11: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Avg. Atomic Mass of Chlorine

To estimate the answer:75% of Cl is 34.969 amu &25% of Cl is 36.966 amu

The final answer has to be between 34.969 amu & 36.966 amu, but closer to 34.969 amu

35.453 amu35.453 amu

Page 12: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Avg. Atomic Mass of Si

92.21% of Si has a mass of 27.97693 92.21% of Si has a mass of 27.97693 amuamu

4.70% of Si has a mass of 28.97649 4.70% of Si has a mass of 28.97649 amuamu

3.09% of Si has a mass of 29.97376 3.09% of Si has a mass of 29.97376 amuamu

Page 13: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Avg. Atomic Mass of Si

0.9221 X0.9221 X 27.97693 27.97693 25.7975 amu 25.7975 amu

0.0470 X 28.97649 0.0470 X 28.97649 1.3619 amu 1.3619 amu

+ 0.0309 X 29.97376 + 0.0309 X 29.97376 0.9262 amu0.9262 amu

28.0856 amu28.0856 amu

Page 14: Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Avg. Atomic Mass of Pb

1.5% Pb-204 1.5% Pb-204 0.015 X 204amu: 0.015 X 204amu: 3.06amu3.06amu

23.6% Pb-206 23.6% Pb-206 0.236 X 206amu: 0.236 X 206amu: 48.62amu48.62amu

22.6% Pb-207 22.6% Pb-207 0.226 X 207amu: 0.226 X 207amu: 46.78amu46.78amu

52.3% Pb-208 52.3% Pb-208 0.523 X 0.523 X 208amu:208amu:108.78amu108.78amu

Sum 207.24amu Sum 207.24amu


Recommended